


One Happy Birthday

by dragonflycas



Category: Supernatural
Genre: Barely Legal, Birthday Sex, Bottom Sam, Established Relationship, First Time, Fluff and Smut, M/M, Pre-Series, Top Dean, Wincest - Freeform, literally he turns 18 like five minutes before they start fucking
Language: English
Status: Completed
Published: 2015-12-09
Updated: 2015-12-09
Packaged: 2018-05-05 19:10:19
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,348
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5387093
Author URL: https://archiveofourown.org/users/dragonflycas/pseuds/dragonflycas
Summary: <blockquote class="userstuff">
              <p>All Sam wants for his birthday is Dean, and Dean's all too happy to oblige.</p>
            </blockquote>





	One Happy Birthday

**Author's Note:**

  * For [fawnspotsam (MyBizarreRomance)](https://archiveofourown.org/gifts?recipient=fawnspotsam+%28MyBizarreRomance%29).



“Not until you’re of age, Sammy,” Dean insisted from the moment Sam brought it up. Sam tried every tactic he could think of to get Dean to change his mind, but nothing worked. Dean was determined. It already felt wrong enough to be in a relationship with his sweet baby brother, he wanted to keep it as above-bar as possible.

They bent the rules a little, sure. There was lots of heavy petting, breathless rutting until they both came in their boxers. At seventeen Sam managed to convince Dean that handjobs “didn’t really count,” and were acceptable substitutes for the interim year. And he only caved to that because they both knew they wanted more; holding back on moral principal didn’t change the way their hormones filled them with lust for each other.

So of course the second Sam’s eyes open on the morning of his 18th birthday he immediately rolls over and presses himself up against Dean, waking his brother by kissing his neck.

Dean stirs slowly, yawning and smiling sleepily down at Sam. “Hey Sammy, happy birthday.”

“Very happy,” Sam hums in agreement, hooking a leg over Dean’s and sliding a hand up under his big brother’s t-shirt to run his fingers over warm skin. Dean’s breath catches as he realizes what Sam was getting at. Already. His heart hammers in his chest as he looks down at the younger Winchester. Sam is the best thing in his life, he’s so pure, and the thought of being his first makes Dean more nervous and scared than any hunt ever has. He doesn’t want to screw up, doesn’t want to accidentally hurt Sam.

“Slow down, baby boy, ’m still half asleep.” He pushes a hand into Sam’s sleep-mussed hair, pulling him in for a languid kiss. The kid shot up like a weed in the past couple years, he’s been pulled out tall and thin like a string bean. He’s all elbows and knees, always running into things because he isn’t used to being so long yet. Dean thinks he’s beautiful.

“All I want for my birthday is you, De,” Sam breathes between kisses, curling his fingers so that his nails scratch lightly over Dean’s chest.

“You got me, Sammy, I’m yours.” Dean lost his virginity six years ago, but he feels just as anxious now as he did back then. He’s been with plenty of girls, and a handful of guys, but none of them were Sam. He didn’t love any of them, hadn’t poured all his happiness into their hands, hadn’t hung his heart around their necks. Sam is his everything, and all he wants in the world is to be good enough for him. He doesn’t feel worthy of being Sam’s first. But if Sam wants him, he could never say no.

Sam sits up and then shifts so that he’s straddling Dean’s hips, hands resting on Dean’s stomach.

“Don’t you want breakfast or somethin?” Dean wants this, god, he’s wanted this since the first time they ever kissed, but still he tries to stall.

“Nope.” Sam pops the ‘p,’ smirking down at his brother and rolling his hips. “Unless you’re asking me to blow you first? Haven’t done that yet either.”

“Fuck, Sammy.” A groan spills from his lips as he pushes his hips up into Sam’s as well, breathing already a little ragged. His sweet baby brother’s sure got a dirty mouth. Maybe he should stop this because if they go through with it he’s sure that Sam’s sinful hips and cotton-candy lips will be the death of him.

“Exactly. You’re catching on.” Sam grins wickedly, leaning down to kiss Dean again. He misjudges the angle this position would bring him down at though, and his lips bump just beside Dean’s nose instead of his lips.

Somehow though, that makes things better. They both laugh softly, and Dean feels some of his tension easing away. This is Sam, so it has to be perfect, but because it’s Sam perfect doesn’t mean having to put on his usual charming, over-confident bad-boy demeanor. Sam knows him, and he knows Sam. They’re comfortable with each other, perfect doesn’t have to mean no mistakes.

“C’mere.” Dean tips his head so that he can meet Sam’s lips in a proper kiss. This is familiar, easy, they’ve kissed plenty in the last year and a half. Their tongues meet, teeth drag over plush lower lips, both of them happily relaxing into muscle memory.

After a minute Sam leans back and strips out of his shirt, and Dean can’t help but follow him up, pressing one hand against Sam’s lower back to hold him steady in his lap. With Sam’s new height Dean’s in the perfect position to press sweet, lingering kisses all over his little brother’s chest. Honestly, he could spend hours just worshipping every inch of Sam’s body, treating him with the reverence he deserves.

Sam presses a hand into Dean’s short hair, grabs and pulls, making the elder gasp against his skin. In retaliation Dean opens his mouth and turns his next kiss into a bite, drawing a low moan from his little brother. Sam’s head tips back as Dean soothes the mark with his tongue, and then takes advantage of the younger’s exposed neck to lean up and suck a dark hickey just over his pulse point, making him shiver and whine.

He slides his hands down Sam’s back, into his boxers, cupping his perfectly round ass in both hands and squeezing. Then suddenly Sam’s moving, getting up, leaving. Dean lets out a whine of protest, reaching after Sam.

“I’m getting lube, just hang on.” Sam rolls his eyes.

“Oh.” Dean sits back, clearing his throat. “I knew that.”

“Sure ya’ did.” Dean narrows his eyes, but he can’t retort because Sam is pulling his boxers down and stepping out of them, and then he is so wiggling his hips on purpose as he walks across the room. All Dean can do is stare as the teen takes his sweet goddamn time fishing the bottle out of the bag.

As he’s walking back Dean strips out of his own sleep shirt and pants, and kicks the blanket off the bed so it won’t get in the way. It’s a bit of an awkward wiggling movement, but he can’t care because Sam’s crawling back onto the bed, and in moments he’s close enough to touch again and that’s all that really matters.

Dean drags him in for a kiss, chasing Sam’s lips when the younger pulls away in order to flop down on his back. He spreads his legs and holds the bottle of lube out to Dean, looking like an invitation to Hell signed by the Devil himself.

“You’re so beautiful, Sammy.” The words cause Sam to blush, all the way down to his collarbone, and Dean leans down to pepper a few soft kisses to his chest before he settles himself between the teen’s legs. “Tell me if it’s too much, yeah? We can stop anytime.”

“It won’t be,” Sam assures, smiling up at Dean with far too much trust. “I’m ready.”

Dean takes a deep breath and nods, popping the top on the lube. He let some drip down over Sam’s hole, making him jump from the cold. Then he poured probably more than necessary over his fingers and shifted so he was leaning over Sam. He wanted to watch his fingers, but it was more important to have a good view of Sam’s face. The stubborn teen would probably never admit to something being uncomfortable, so Dean was determined to keep a close eye on his reactions and judge for himself when a break or change was needed.

His first finger pushes in easily, but god Sam is still so hot and tight around him, the sensation making his dick twitch and drool precome as he imagines how it will feel to actually sink into him. Sam sucks in a sharp breath, hazel eyes dark and glazed as he stares up at Dean. As he starts to move his finger slowly in and out, he leans down and captures Sam’s lips in a fierce kiss.

“More,” Sam croaks out after a minute, breaking the kiss and whining as he rocks his hips. “C’mon, De, need more.” Dean’s in no place to argue, already wrecked just by the way Sam’s moaning for him. He pushes in a second finger and Sam groans, fingers twisting in the sheet under them.

“You’re so good for me, baby boy,” Dean sighs, leaning down and kissing Sam’s neck, then biting a hickey into the point where it meets his shoulder. Sam moans in answer, arching off the bed and pushing his hips back to meet Dean’s movements as the elder brother starts scissoring his fingers.

Now that they’ve started this, Dean knows they’re going to be all over each other every chance they get. Sam is the most beautiful thing in the world, and he looks even better like this, splayed out and desperate for Dean. Dean’s always thought of him as innocent and pure, always thought he had to keep Sam protected from the evils in the world. Now he feels like one of those evils, but defiling Sam is the most pleasurable thing he’d ever done in his life.

“More,” Sam demands again once more time has slid past. It seems like they’re trapped inside a bubble of a moment, locked together in a tiny eternity. Dean obliges, latching his mouth onto one of Sam’s nipples as he presses in the third finger, trying to distract him from the stretch.

Sam takes it so well, rocking his hips as Dean moves his fingers in and out, forcing him to go faster, deeper, his moans and whimpers going straight to his big brother’s cock.

“So eager for me,” Dean murmurs, nosing Sam’s jaw. “Just a natural little cockslut, aren’t you?”

Sam groans, turning his head to look up at him. “Yeah, so fuck me already.”

“Christ, Sammy, y’gotta stop saying shit like that,” Dean groans, resting his forehead against Sam’s shoulder.

“But if I keep sayin’ it, will you fuck me? C’mon, I’m ready, I want you.”

“You’re gonna be the death of me,” Dean sighs as he pulls his fingers back slowly. Sam whines at the loss, and then moves to sit up. “Where’re you going?” Dean frowns, and Sam laughs softly as he puts a hand on Dean’s shoulder, simultaneously hoisting himself up and pushing Dean back into the bed.

“Lay down, I wanna ride you.” Dean swears again, loud enough to be heard through the thin motel walls if anyone is listening. He pushes himself up the bed, shoving the pillows together so that he can lean back against them. Once he’s settled Sam climbs up so he’s straddling his hips, just as he was earlier.

He braces himself against Dean’s chest with one hand, and reaches back to wrap the other around his cock. Then he sinks down and Dean swears this is the closest he’s ever come to a religious experience.

“Fuck, Sammy.”

“You’re fond of that phrase.” The teasing would work better if Sam’s voice wasn’t also cracked and breathless, and Dean retaliates by slamming his hips up, making Sam choke out a broken moan of his name in turn.

He’s so tight and hot and gorgeous and everywhere, and Dean’s 22 but he feels 16 and ready to come at any second. He takes a few deep breaths to steady himself as sam pauses, fully seated on his dick. Then Sam starts moving and he swears again, his hands coming up to grip the teen’s slim hips.

Sam’s hips roll with an ease that can only be called practiced, and Dean suddenly doubts his assumption that he must be his little brother’s first. The thought of someone else touching his Sammy like this makes his hands tighten, nails pressing crescents into Sam’s skin and making him whine.

He moves slow at first, and Dean’s happy to let him set the pace, to follow his lead. He rocks his hips up in time with Sam’s, matching the movements. They fall together so easily, an extension of how well they know each other, inside and out.

Soon sam starts speeding up his movements, lifting himself and then dropping back down on Dean’s cock, fast and hard, punching ragged breaths and low moans out of them both. The only words either of them manage to form is each other’s names, gasped out between kisses as Sam curls himself over enough for their lips to meet.

After a while Dean moves a hand between them and wraps it around Sam’s leaking dick, jerking him off in time to the movement of their hips. “Not gonna last long, baby boy,” he groans, panting as he thrusts up sharply into Sam. “Wanna see you come first, come for me.”

Sam moans in answer, speeding up his movements even more, nails raking red lines down Dean’s chest as he fucks himself on his big brother’s cock. “Yeah, just like that,” Dean croons, rubbing his thumb over the head of Sam’s cock, jerking him fast and hard until Sam’s tensing up. The teen drops himself down one last time, grinds his hips against Dean’s, his head dropping back with a cry of Dean’s name the neighbors must be able to hear. He comes over Dean’s chest, trembling through his orgasm, muscles clenching and unclenching around Dean and making him see stars.

Dean strokes Sam through it, and then starts moving again. Just a few more short, sharp thrusts are enough to push him over the edge so he can follow Sam, coming deep inside his little brother. He wraps his arms around Sam and pulls him in close to his chest, both of them panting and shaking with the aftershocks.

“Happy birthday,” Dean croaks out a soft laugh after a minute of silence, and Sam echoes him, kissing his shoulder and nuzzling close, happy to rest there until he can feel his legs again.

“Best birthday ever.”


End file.
